The agreement includes FPA008, which is in Phase I development for immunology and oncology indications. Preclinical models of several cancers have shown that the drug reduces the number of immunosuppressive tumour-associated macrophages in the tumour microenvironment, thereby facilitating an immune response against them.

Explaining his firm’s interest in the deal, BMS chief scientific officer Francis Cuss said the approach “represents a potentially important complementary immuno-oncology mechanism of action to the T-cell directed antibodies and co-stimulatory molecules in our pipeline”.

As per the terms of the agreement, B-MS will make an upfront payment of $350 million to Five Prime, and takes on responsibility for development and manufacture of FPA008 across all indications, subject to the latter’s option to carry out certain future studies at its own cost.

Five Prime will continue to conduct the current Phase Ia/b trial evaluating the combination of BMS' Opdivo (nivolumab) and FPA008 in six tumour settings, announced as part of the companies’ initial clinical collaboration in November 2014, through to completion.

BMS is also responsible for global commercialisation, but Five Prime will retain US co-promotion rights. In addition to the upfront payment, Five Prime is also eligible to receive up to $1.05 billion in development and regulatory milestone payments per anti-CSF1R product for oncology indications and up to $340 million for non-oncology indications, as well as double digit royalties.